The present invention relates to an information generating apparatus for transmitting and receiving elastic waves through a propagation medium and for generating information to be used for controlling/monitoring a system.
For example, a railroad crossing gate control operation performed in a current railway transportation system will be described hereinbelow.
When a train is detected by a train detection device that is provided at an approach detection point which is established at a predetermined place before a railroad crossing, a warning device starts sounding, and after a lapse of a predetermined time period since a sounding start point of time, a gate arm of a railroad crossing gate is caused to descend, as illustrated in FIG. 1. Thereafter, when it is detected that the train having entered the railroad crossing leaves there, the sounding operation of the warning device is stopped and moreover, the gate arm is caused to ascend.
Incidentally, a time period Tx between a moment from when the gate arm starts descending until the train enters the railroad crossing, should be secured as, for example, a time period required for an automobile or the like left in the railroad crossing to get out there, and should be equal to or longer than a predetermined time period (of, for instance, 15 seconds). Additionally, the sounding operation of the warning device, which is performed to inform an automobile or the like traversing the railroad crossing of the fact that the train approaches the railroad crossing, should be commenced a predetermined time (To shown in this figure, which is, for example, 30 seconds) or more before a train enters the railroad crossing.
Hitherto, for the purpose of securing the aforementioned time periods Tx and T0, the timing with which the sounding operation of the warning device is started (namely, the timing with which a crossing inhibition command is issued) is controlled on the assumption that, among trains passing through the railroad crossing, the fastest one passes therethrough.
However, there are various kinds of trains, which run through a same running section, from a high-speed express train to a low-speed freight train. Thus, if the sounding operation is started with the same timing by assuming that, among trains passing through a railroad crossing, the fastest one passes therethrough, in the case that a train of which speed is lower than that of the assumed train, passes through the railroad crossing, it takes time, which is longer than required, until the train reaches the railroad crossing after the sounding operation of the warning device is started, or after the gate arm descends. Consequently, the aforementioned time periods T0 and Tx become extremely long, so that a time period, during which automobiles and passers-by are prohibited from traversing the railroad crossing, becomes longer than required.
To solve the aforesaid problems, there has been employed a railroad crossing gate control operation that is referred to as a constant time control operation of timing-controlling in such a manner that the lengths of the time periods T0 and Tx are constant (see, for instance, Yoshimura and Yoshikosi, xe2x80x9cSignalxe2x80x9d, Koyusha, 1958).
A method for performing a constant time control operation is a delayed control method by which kinds of trains such as an express, a local train and a freight train is detected and then, if a train is of the kind that runs at a low speed, the sounding operation of the warning device and the operation of the gate arm are delayed.
However, in the case of employing such a delayed control method, when a train which usually travels at a high speed, runs by reducing the travelling speed thereof owing to an occurrence of a trouble over train operations, a sounding time period, during which the warning device sounds, and a railroad crossing closing time period, during which the railroad crossing is closed by the crossing gate, become long, similarly as in the aforementioned case. Further, trains assigned to the kinds of low-speed trains, for example, a freight train should run at a speed, which is lower than a speed limit, after passing through the approach detection point (namely, the train detection point), even in the case where the freight transported by the train is light and the train is thus in the condition that the travelling speed thereof can be easily increased. Moreover, the delayed control method requires troublesome operations of allocating the kinds to each train and of managing data representing the allocated kind.
Moreover, there has been employed a control method, by which the travelling speed of a train is detected at an approach detection point and the timing is controlled on the basis of the speed detected at that time, as another method of performing a constant time control operation. In this case, the troublesome operations for managing the allocated kinds of trains are unnecessary.
However, in the case of this method, if the train is accelerated after passing the approach detection point, the time periods T0 and Tx are shortened. Thus, there are still restraints imposed on the speed at which the train runs after passing through the approach detection point.
As above stated, conventional railroad crossing gate control systems have various defects which should be improved in various respects.
Furthermore, in the case of managing train traffic, a track is partitioned into a plurality of sections. Then, the presence/absence of a train is detected in each of the sections. Subsequently, the entrance of the train into each of the sections and the leaving thereof from each of the sections are controlled. In such a train traffic management control system, a tracking circuit is employed as a conventional train detection device for detecting the presence/absence of a train in each of the sections.
Principle of the train detection performed by using such a track circuit will be described hereinbelow.
In each of a plurality of sections (referred to as a block section) obtained by partitioning a track, on which a train travels, thereinto, a power supply for feeding a signal current to be used to detect a train is connected to a pair of rails at the terminating side (namely, at the side from which the train leaves), while a track relay to be excited and driven by the aforementioned signal current is connected to a pair of rails at the beginning side (namely, at the side into which the train comes). Thus, a closed circuit for driving the track relay is constituted by utilizing a pair of rails as a part of an energizing path.
In such a constitution, when no train is present in a block section, electric current flows through the aforementioned closed circuit, so that the track relay is exited (thus, is raised) and an output signal indicating the absence of a train is generated as a result of a relay contact operation. In contrast, when the train enters the block section, wheels provide a short circuit between a pair of rails. Thus, electric current does not reach the track relay provided at the beginning side of the block section, so that the track relay is in a non-excited condition (thus, falls) and an output signal indicating the presence of a train is produced as a result of a relay contact operation. In this way, the presence/absence of a train is detected correspondingly to each of the block sections.
However, the conventional train detecting system, in which a train is detected by a track circuit utilizing the aforementioned electric circuit, has encountered a problem in that, although this system can detect whether or not a train is present in a block section, the system cannot specify a place, at which the train is present, in the block section.
Additionally, it is important for achieving a safe running operation of a train in a railroad transportation system to detect whether or not there is a rupture in rails.
There have been provided conventional devices for detecting a rupture in rails, an example of which will be described hereinafter.
Namely, a rail is insulated at predetermined intervals. Therefore, in a segment between insulated parts thereof, a transmitter is provided at an end portion thereof and a receiver is provided at the other end portion thereof. Thus, an electric current path is formed by utilizing the non-insulated segment of the rail. Further, if rupture takes place in the rail and portions of the rail are separated at a rupture part from one another, no electric current sent from the transmitter is transmitted to the receiver through a segment of the rail. Consequently, the device is adapted so that the presence/absence of a rupture in the rail is checked according to whether or not electric current supplied from the transmitter is transmitted to the receiver.
However, although the rupture occurring in the rail can be reliably detected by the conventional device in the aforementioned case of the ruptured condition in which the portions of the rail are separated at the rupture from one another, an electric current fed from the transmitter is allowed to flow through a part, which is not completely broken off, and can be received by the receiver according to the conventional method in the case that the rail is not completely ruptured but the portions thereof are partly connected at the rupture with each other. Moreover, in the case that the portions of the rail are in contact with each other even if the rail is completely ruptured, an electric current flows through the port ions thereof can be received by the receiver. Consequently, the conventional rupture detection system has faced a problem in that this conventional system can detect only a condition where the rail is ruptured to the extent that the portions, into which the rail is divided at the rupture, are completely separated from one another.
In recent years, there have been demands for high-speed and high-density transportation in the railroad transportation system, with the intention of enhancing the efficiency in carrying passengers. Moreover, it has been requested that the aforementioned problems in respect of the railroad crossing gate control system, the train detection or the rail rupture detection are solved by simultaneously securing the higher safety and reliability than ever.
The present invention is accomplished in view of the aforesaid circumstances and aims at solving the aforementioned problems by transmitting and receiving elastic waves through a movement path of a mobile unit as a transmission medium and by generating information to be used for controlling/monitoring associated elements of a control system for performing control operations on the mobile unit, such as a railroad crossing gate control operation, a train detection operation or an operation of detecting an occurrence of rupture in the movement path, based on an elastic wave reception signal.
Thus, there is provided an information generating apparatus using elastic waves in accordance with the present invention, which employs a movement path of a mobile unit as a transmission medium, and which is constituted by comprising an elastic wave transmitting device for transmitting elastic waves to the transmission medium, an elastic wave receiving device for receiving elastic waves transmitted from the elastic wave transmitting device through the transmission medium, and an information generating device for generating information that is necessary for controlling/monitoring associated elements of a control system for performing control operations on the mobile unit based on an elastic wave reception signal received by the elastic wave receiving device.
With such a constitution, information needed for controlling/monitoring a mobile unit control system, for example, for performing various control operations on a railroad transportation system can be generated by using elastic waves.
In this case, the apparatus of the present invention may as well be constituted so that a transmitter of the elastic wave transmitting device and a receiver of the elastic wave receiving device are in contact with the transmission medium.
With such a constitution, the propagation speed of elastic waves is high and thus the information can be obtained quickly.
In the case that the mobile unit is a train, the apparatus of the present invention is constituted so that the information generating device comprises a propagation time measuring device for measuring an elastic wave propagation time during which an elastic wave propagates between the train and a railroad crossing placed partway through a train movement path, a distance computing device for computing a distance between the train and the railroad crossing, based on the measured propagation time, a speed computing device for computing a train speed based on a change in the computed distance, and a control device for controlling timing, with which railroad crossing traversing inhibition command information is generated, based on the latest computed distance and train speed, and the railroad crossing traversing inhibition command information is generated under the control of the control device.
With such a constitution, the distance between the train and the railroad crossing and the train speed are computed every transmission of an ultrasonic wave. Further, the timing, with which the railroad crossing traversing inhibition command information is generated, is controlled on the basis of the latest computed distance and train speed. Thus, even if the train speed changes after the train passes through the approach detection point, the traversing inhibition command information can be generated with suitable timing in response to the change in the train speed.
Further, the apparatus of the present invention may as well be constituted so that a running pattern information transmitting device for transmitting a train running pattern information signal is provided in the train, while a running pattern discriminating device for discriminating running pattern information transmitted from the train is provided in the information generating device, the control device comprises an individual-running pattern boundary distance setting device for setting a boundary distance between the railroad crossing and the train, by which a previously set time can be secured from the generation of sounding operation starting command information until when the train enters the railroad crossing, based on the computed train speed correspondingly to each of the running patterns, a selection device for selecting a boundary distance corresponding to a running pattern discriminated by the running pattern discriminating device, and a judgment device for comparing the distance, which is computed by the distance computing device, with the boundary distance selected by the selection device and for judging whether or not the computed distance is equal to or less than the boundary distance, and a moment, at which the computed distance becomes equal to or less than the boundary distance, is set as a time at which the sounding operation starting command is generated.
With such a constitution, the train transmits a train running pattern, such as an acceleration pattern, a deceleration pattern or a constant speed pattern, to a ground facility that controls the timing with which the sounding operation starting command information corresponding to the transmitted running pattern is generated. Thus, even in the case that the running pattern of the train approaching the railroad crossing is different, the timing, with which the sounding operation starting command information is generated, can be controlled suitably.
The apparatus of the present invention may as well be constituted so that an elastic wave transmitting device and an elastic wave receiving device are provided in the train and the ground facility, respectively, and, when an elastic wave transmitted through a rail from the ground facility is received by the train, an elastic wave is transmitted from the train as a reply without delay, and the elastic wave propagation time, during which an elastic wave propagated between the train and the railroad crossing, is measured, based on a time between a moment, at which the ground facility starts transmitting an elastic wave to the train, and another moment at which the ground facility receives an elastic wave from the train.
With such a constitution, the necessity for synchronizing a transmitting-side device with a receiving-side device is eliminated. Consequently, the constitution of the apparatus can be simplified.
Furthermore, the apparatus of the present invention may as well be constituted so that the information generating device has a reception acknowledgement device for acknowledging reception of the elastic wave, and, when no reception acknowledgement signal is sent from the reception acknowledgement device in a condition that a detection signal indicating the detection of a train approaching the railroad crossing is generated, traversing inhibition command information is immediately generated.
With such a constitution, in the case that the reception of an ultrasonic wave reception signal cannot be confirmed and thus no information on the distance and speed of a train approaching the railroad crossing can be obtained, a traversing inhibition command is immediately issued. Thus, the safety of an automobile or a passenger traversing the railroad crossing can be secured.
The apparatus of the present invention may as well be constituted so that the information generating device has a detection device for detecting the presence/absence of the mobile unit based on a reception condition of an elastic wave received by the elastic wave receiving device and for generating mobile unit presence/absence.
With such a constitution, the mobile unit presence/absence information can be obtained by using an elastic wave. This can be applied to the detection of a train in the railroad transportation system.
In the case that the mobile unit runs on two rails which are parallel with each other, the apparatus of the present invention may as well be constituted so that the elastic wave transmitting device is placed at an end portion of one of the two rails, the elastic wave receiving device is placed at an end portion, which is on the same side as the elastic wave transmitting device, of the other of the two rails, and, when an elastic wave is transmitted from the one of the two rails to the other thereof through wheels of the mobile unit and is then received by the elastic wave receiving device, the detection device generates mobile unit presence information.
With such a constitution, if no mobile unit is present, the elastic wave receiving device receives no elastic waves. In contrast, if a mobile unit is present, an elastic wave is propagated from one of the rails to the other thereof through the mobile unit and is received by the elastic wave receiving device. The detection device is adapted in such a manner as to detect the presence of the mobile unit by inputting an elastic wave reception signal. Moreover, the position of the mobile unit can be detected by measuring the time between the initiation of the transmission of an elastic wave and the reception of this elastic wave.
The apparatus of the present invention may as well be constituted so that a sliding contact member, which rides astride and slides on the two rails and exhibits an elastic wave propagation speed characteristic being superior than that of the mobile unit, is provided at a front portion of the mobile unit.
With such a constitution, the transmission loss of elastic waves propagated through the mobile unit can be suppressed. Thus, the mobile unit can be detected further surely.
Additionally, the apparatus of the present invention may as well be constituted so that a connecting member for connecting between rails is provided at a rail position that is a previously set predetermined distance, away from the elastic wave transmitting device and the elastic wave receiving device.
With such a constitution, if the elastic wave propagation speed characteristic of the connecting member is already known, the distance, which is measured from the propagation time of the signal received through the mobile unit, therefrom to the mobile unit can be corrected from an amount of a change in the propagation time of the reception signal propagated through the connecting member. Thus, the position of the mobile unit can be detected with good precision by reducing the influence of a change in the elastic wave propagation speed characteristic of the rails or the like, which is caused by a change in temperature. Moreover, if the elastic wave propagation speed characteristic of the connecting member is set in such a manner as to be nearly the same as that of the mobile unit, the position of the mobile unit can be detected only by detecting that the signal received through the connecting member is matched with the signal received through the mobile unit.
The apparatus of the present invention may as well be constituted so that the elastic wave propagation speed characteristic of the connecting member is slower than that of the mobile unit.
With such a constitution, the connecting member can be utilized as a delay element for the elastic wave propagation. The position of the connecting member can be set in the vicinity of the elastic wave transmitting device/the elastic wave receiving device. Consequently, the operation of establishing the connecting member and the maintenance thereof can be facilitated.
The apparatus of the present invention may as well be constituted so that, when the mobile unit travels on the two rails, which are parallel with each other, in the case where the presence/absence of the mobile unit is detected by comparing the level of a reception signal with a threshold value, the elastic wave transmitting device is placed at an end portion of one of the two rails, and the elastic wave receiving device is placed at an end portion, which is at the same side as the elastic wave transmitting device, of the other of the two rails, and a plurality of connecting members, which are superior to the mobile unit in elastic wave propagation speed characteristic, are established in such a way as to be spaced from one another and to connect between the two rails, and so that a distance from the elastic wave transmitting device to each of the connecting members and a distance from the elastic wave receiving device to each of the connecting members are previously set.
With such a constitution, a reception signal received through each of the connecting members is received with time delay corresponding to the connection position thereof. Thus, the position of the mobile unit can be immediately detected by sensing a reduction in the signal level of the reception signal due to an increase in propagation loss that is generated as a result of the fact that the mobile unit passes through each of the connecting-member mounting positions.
Further, the apparatus of the present invention may as well be constituted so that a detection device is established in a block section equipped with a track circuit for detecting a train, and a system of detecting a train by using a track circuit is utilized together with a system of detecting a train by using an elastic wave.
With such a constitution, the detection of a train can be achieved by a duplex system for detecting a train by using a track circuit and for detecting a train by using an elastic wave. Consequently, the reliability of the detection of a train is enhanced.
The apparatus of the present invention may as well be constituted so that the information generating device has a judgment device for making a judgment on presence/absence of rupture in the movement path, based on a reception condition of an elastic wave received by the elastic wave receiving device and for generating information representing presence/absence of rupture in the movement path.
With such a constitution, the detection of rupture in the movement path is performed by using elastic waves. Thus, even in the partial rupture case that portions of the movement path are still in contact with one another although the movement path has been ruptured, it is possible to detect rupture in the movement path, because the reception condition of an elastic wave is different from that of the wave in the case of a normal state.
The apparatus of the present invention may as well be constituted in such a manner as to have a checking device for checking a receiving function based on a reflection wave at a movement path joint in an end portion of a rupture checking section.
With such a constitution, it can be monitored at all times whether or not the function of the elastic wave receiving device is normal. Consequently, the reliability of the detection of rupture is enhanced.
The apparatus of the present invention may as well be constituted so that, when the movement path consists of a plurality of running sections electrically insulated from one another at rail joints, respectively, close section end portions of at least adjacent running sections among the plurality of running sections are connected by device of insulating bypass propagation media adapted to propagate an elastic wave by bypassing the rail Joint portions, and the plurality of running sections connected by the bypass propagation media are employed as the rupture checking sections, and a connecting member for connecting between the rails parallel with each other, is formed with an insulating matter.
With such a constitution, the rupture detection device can be also used together with the track circuit for detecting a train. In addition, the presence/absence of rupture in a plurality of track circuits can be monitored only by such a single rupture detection device.
Furthermore, the apparatus of the present invention may as well be constituted so that an elastic wave and an electric signal are transmitted from a predetermined position in the vicinity of a home signal to a train through rails by being synchronized with each other, a train speed is calculated in the train based on a time delay between the receptions of the transmitted electric signal and elastic wave, and speed pattern information, which corresponds to a distance from the home signal stored in an information storage device mounted on the train, is compared with the calculated train speed, and when the home signal is in a stop aspect, a braking device of the train is operated if a stopping calculated train speed is higher than a pattern speed.
With such a constitution, an ATS (Automatic Train Stop) apparatus using elastic waves can be realized.
Further, the apparatus of the present invention may as well be constituted so that elastic waves are transmitted from each elastic wave transmitting device to two rails which are parallel with each other, respectively, the elastic waves from the rails are received by each elastic wave receiving device in the train, respectively, and limit speed information representing a limit speed of the train is imparted to the elastic waves to be transmitted to the rails, respectively, and then the elastic waves are transmitted thereto, respectively.
With such a constitution, the elastic waves to be transmitted to the rails, respectively, are easily made to be independent of one another. Thus, according to the present invention, the ATC (Automatic Train Control) apparatus can be easily constituted as a duplex system, which could not been constituted in the conventional apparatus in which the limit speed information is given to the train by using an electric signal.